Dual hot-air heater unit for fireplaces



May 24, 1949. R. D. RUSSELL DUAL HOT AIR HEATER UNIT FOR FIREPLACES 5 Sheets-Sheet 1 Filed Oct. 18, 1946 May 24, 1949. R. D. RUSSELL DUAL HOT AIR HEATER UNIT FOR FIRE-PLACES Filed Oct. 18,- 1946 3 Sheets-Sheet 2 May 24, 1949. R. D. RUSSELL 2,471,351

DUAL HOT AIR HEATER UNIT FOR FIREPLACES Filed Oct. 18, 1946 3 Sheets-Sheet 5 3 wbwwtm Patented May 24, 1949 DUAL HOT-AIR HEATER UNIT FOR FIREPLACES Robert D. Russell, St. Petersburg, Fla.

Application October 18, 1946, Serial No. 704,256

Claims.

This invention relates to dual hot air heating systems for homes or other enclosures of the general type in which a primary heater, such as an oil or gas burner, is associated with an auxiliary heater, such as a wood-burning or coal-burning fireplace, in a manner such that the heaters may be operated either independently or conjointly to heat the air circulated within the enclosure.

An important object of my invention is to provide a dual heating system of the above character including means for controlling the flow of circulation air relative to the primary and auxiliary heaters in such a manner that the circulation air may be caused to travel in intimate heat-exchange relation With portions of the auxiliary heater when the latter is in service to effect the heating of the air, and may be deflected away from such portions when the auxiliary heater is out of service so as not to unduly chill the air.

A further object of my invention is to provide a dual heating system of the above character including primary and auxiliary heaters located side-by-side on substantially the same level, the system being especially suitable for installation as a unit within the fireplace areas of homes having no basements and which requires little or no excavation work in its installation.

Another object of my invention is to provide a dual heating system of the above character in which the primary and auxiliary heaters are combined into a unitary structure to facilitate shipping, handling and installation, which unit is adapted to be incorporated in the usual fireplace area of a home either at the time the building is erected or, without a great deal of alteration or expense, 'as a later improvement upon such fireplace.

Still another object of my invention is to provide a dual heating system of the above character comprising a heat chest enclosing the primary and auxiliary heaters and including means for causing the circulation air to flow into and out of heat-exchange relationship with the auxiliary heater during its passage through the heat chest. In the preferred embodiment of my invention, the flow-control means are mounted for coordinated operation with a damper for controlling. the exhaust of combustion gases from the auxiliary heater, the arrangement being such that when the exhaust outlet from the auxiliary heater is closed-which occurs when the auxiliary heater is out of servicethe air entering the heat chest, which ordinarily would scrub the cold metal parts of the auxiliary heater and be more or less chilled thereby, is directed away from said parts.

An additional object of my invention is to provide a dual heating system of the above character including primary and auxiliary heaters adapted to be installed as a unit within the fireplace areas of homes, and a heat chest enclosing the heaters and having a riser leading upwardly therefrom and surrounding the flue of the primary heater, whereby the circulation air in the riser is heated by the flue throughout a substantial portion of its travel from the heat chest to its points of discharge into the enclosure.

For another object, my invention aims to provide a dual heating system of the above character including primary and auxiliary heaters adapted to be installed as a unit within the fireplace areas of homes, the chimney for the auxiliary heater being provided adjacent its lower end with means for avoiding excessive downdraft and for preventing rain water, that tends to collect in the bottom of the chimney during a heavy or protracted downpour, from spilling over into the auxiliary heater.

Another object of my invention is to provide a dual heating system of the above character in which the primary and secondary heaters are combined into a, single unit suitable for installation in the fireplace areas of homes and being enclosed in masonry work to reduce the fire hazard.

Other objects and advantages will be apparent from the following detailed description of a preferred embodiment of the invention, reference being had to the annexed drawings, in which:

Figure 1 is a perspective view of a dual heating unit, with parts broken away to better show the primary and auxiliary heaters and the housing enclosing such heaters;

Figure 2 is a perspective view of the dual heating unit of Fig. 1, viewed from its rear, the enclosing frame and housing being omitted for greater clearness;

Figure 3 is a perspective view of the dual heating unit enclosed within its housing;

Figure 4 is a side view in vertical cross-section.

through the dual heating unit showing the unit installed in the brick fireplace area of a home;

Figure is a front view of the dual heating unit shown in Fig. 4, parts being broken away to show the interior of the burner casing;

Figure 6 is a plan view of the dual heating unit taken on the line 6-6 of Fig. 5; and

Figure 7 is a detail view of a front corner of the dual heating unit showing the manner in which the housing is attached to the front wall of the fireplace shell.

The dual heating system illustrated in the drawings comprises generally a primary heater A and an auxiliary heater B both enclosed within a housing C defining a heat chest through which the air for circulating within the home or other enclosure is passed. The assembly of primary and auxiliary heaters A and B and the enclosing housing C constitutes a dual heating unit adapted to be mounted in the space afforded by the usual fireplace area of a home. The circulation air for heating the home is supplied to the heat chest from an air chamber D located below the duel heating unit in the space between the ground and the first fioor levels of the home, and the heated air leaving the heat chest passes upwardly through a riser E from which it is delivered to the rooms of the home by way of one or more distributing ducts F. The circulation air after giving up its heat to the enclosure is returned to the air chamber D, via one or more return-air pipes G extending between the air chamber and the floor level or levels of the home. This general arrangement of the dual heating system is best indicated more or less schematically in Fig. 1.

The heating system will now be described in greater detail. The primary heater A comprises an elongated box-shaped casing I made of steel plates welded together to form a gas-tight compartment within one end of which is located an oil burner 2 (Fig. 5). The oil burner is connected by a burner pipe 3 extending through the end walls of the burner compartment and heat chest to a motor-driven device 4 mounted outside the housing C for delivering oil from a fuel tank (not shown) and also air to the burner.

Disposed horizontally above the burner in spaced relation thereto is a metal baflle plate 5, and this baffle plate extends between the side walls of the burner compartment and from one end of the compartment to a point spaced inwardly from its other end where it terminates in a downturned portion 5a. A transparent inspection window 6 is mounted in an end wall of the casing. The waste products of combustion escape from the burner compartment through a vertically disposed metal flue pipe 1 communicating with the top of the compartment nearest that end of the compartment containing the burner 2. Thus, the hot gases of combustion in their travel from the burner 2 to the flue pipe 1 are impelled by the baffle plate 5 to pass along the lower zone of the compartment until they encounter the downturned baffle portion Ed by which they are deflected downwardly and outwardly against the end wall of the compartment, after which they rise into the upper zone of the compartment and reverse their course throughout approximately the full length of the compartment before venting into the flue pipe. By virtue of this construction, the gases of combustion are caused to give up a substantial portion of their heat to the top, bottom, side and end walls of the compartment, thus resulting in an efiicient transfer of the heat 4 through these metal walls to the air in the heat chest.

Located adjacent and parallel to the burner casing l in side-by-side relation is the auxiliary heater B which takes the form of an open-front fireplace shell 8. This shell is made of heavy steel boiler plate tightly welded together so as to provide two end sections 8a, a back section 81), a hearth section 80, and a front section 8d reaching substantially beyond the planes of the end sections and terminating in rearwardly turned flanges 8c. The back section 8b extends vertically upward from the bottom plate for approximately half of its length and then inclines toward the front of the shell, as best shown in Figs. 1 and 4.

The shell 8 is adapted to serve as a fireplace for the burning of coal or wood upon an open hearth. For removing the waste products of combustion, an upwardly and rearwardly inclined conduit defining a throat 9 of rectangular crosssection leads off from an exhaust opening at the rear of the shell above the back plate 8b and discharges into a flat-bottomed smoke box ill (Fig. 2) positioned in line with and closing the lower end of a brick chimney II which extends outdoors through the roof of the home in the usual manner. The roof of the throat is forwardly projected, as indicated at 9a, to close the upper end of the shell, while one of the side walls 912 of the throat (Fig. 6) is diagonally disposed relative to a vertical plane so as to allow clearance for the flue pipe 1, which latter extends vertically parallel to the chimney ll.

Overlying the air chamber D and enclosing the burner casing l and the fireplace shell 8 is a housing l2 which constitutes the heat chest C. The housing i2 is made of heavy steel boiler plates welded to a generally box-shaped skeleton frame I3 which frame embraces and ties together into a unitary structure the casing l and shell 8. This housing is open at its bottom and comprises two end walls l2a, a back wall 12b and an inclined top wall l2c, which latter parallels throughout a portion of its area the sloping roof of the rearwardly and upwardly inclined throat 9. The end walls of the housing are located in spaced relation to the corresponding end walls of the burner casing I and shell 8, and the forward vertical marginal portion of the end walls of the housing overlap and are welded to the flanges 8a on the front section 8d of the shell. This allows the free flow of air from the air chamber D over the exposed heating surfaces of the primary and auxiliary heaters. A transparent inspection window I4 is mounted in the end wall of the housing in alignment with the window 6 in the casing I, whereby the condition of the burner may be viewed from outside the housing.

The top wall I20 of the housing comprises a flat rearwardly and upwardly inclined portion which merges into a flat horizontal portion. A warm air outlet I5 is formed in the horizontal portion of the top wall to afford passage for the flue pipe 1 but being oversize with respect thereto. The outlet I5 opens into the lower end of the riser E which has sheet metal side walls 16 and is closed at its upper end by a cover plate Ilia. The flue pipe projects through this cover plate and discharges into a chimney lla, which may extend contiguous to chimney II, or may be a partitioned section thereof.

The housing l2 containing the primary heater A and the auxiliary heater B is adapted to be accommodated within the area customarily allotted to the brick fireplace in homes, the open front of the shell 8 facing the room and defining a metal-lined fireplace. The burner casing I and fireplace shell 8 are rigidly secured to the skeleton frame l3 by means of gusset plates ll affixed to the end Walls of the casing and shell. The open bottom of the housing rests upon the upper edges of the masonry walls l8 constituting the sides of the air chamber D which chamber lies between the ground and the first floor levels of the home. The top of the air chamber and the bottom of the housing communicate through an air inlet opening 22. Air is sucked into the air chamber by a motor-driven blower l9 (Fig. 4) via returnair pipes G and this air is delivered through a partition 24 into that part of the air chamber located immediately below the dual heating unit. The return-air pipes at their inlet ends are capped with grilles 20, which grilles may be provided at such locations in the floor or floors of the home as may be found most expedient. An air filter screen 2| is located between the returnair pipes G and the intake side of the blower for removing dust carried in suspension in the return air.

An advantageous feature of the present invention is the provision of deflecting means for directing the circulation air rising from the air chamber D into and out of contact with the end walls of the fireplace shell 8, so that when the fireplace is in service the air will scrub these hot end walls and be heated thereby, but when the fireplace is out of service the air will be by-passed around the end walls so as to avoid excessive cooling of the air through contact with the cold metal surfaces. These deflecting means take the form of deflector plates 23 which are pivotally suspended in the spaces at opposite ends of the shell separating the end walls of the shell and housing so as to swing from a generally upright position (indicated in full lines in Fig. 4) for allowing the air rising through the opening 22 to flow upwardly along the side walls of the shell, to a generally horizontal position (indicated in dotted lines in Fig. 4) in which latter position the air is deflected rearwardly of the shell and into contact with the hot walls of the burner casing I. When the deflector plates are in lowered position one end abuts the inner face of the front section 801 of the fireplace shell and their other end seats against rearwardly and upwardly inclined shelves 25 bridging the space between and supported by the end walls of the shell and housing and serving as stops for limiting the clockwise rotation of the deflector plates.

A damper 26 (Fig. 4) is secured to a horizontal cross-rod 2! extending between and journaled within the end walls 8a of the fireplace shell 8. This damper is concealed behind the upper portion of the front section 8d of the shell and, as best indicated in Fig. 4, is adapted to swing from a position in which the entrance to the throat 9 is open, allowing the gases of combustion to flow from the fireplace into the chimney H. to another position in which the throat entrance is closed, barring the reverse flow of air down the chimney into the fireplace. The damper will ordinarily occupy this latter position when the fireplace is not in service.

In order to coordinate the operation of the damper with that of the deflector plate a pair of connecting rods 28. located in the space intermediate the end walls of the shell and the housing, extend between cranks 29, fixed upon the cross -rod 21, and eye bolts 30 secured to the defiector plates 23. The arrangement is such that when the damper 26 is swung to closed position with respect to the throat 9, the deflector plates are rocked to lowered position, as indicated in dotted lines in Fig. 4, and when the damper is swung to open position, the deflector plates are moved to raised position, as indicated in full lines in this figure. Affixed adjacent one end of the cross-rod 21 and extending forwardly to a conveniently accessible position outside of the fireplace shell is a handle 21a for manually rotating this cross-rod and simultaneously operating the damper and deflector plates.

The heated air in the riser E is led off by way of one or more distributing ducts F branching 01f therefrom and. discharged through registers 30 into the various rooms or elsewhere within the enclosure. While only one distributing duct has been shown in Fig. 1 of the drawings, in usual practice it will be desirable to provide a number of these ducts so as to insure the most eificient heating of the home. For example, when the house is two or more stories high, the ducts should preferably serve each of the floor levels.

In order to prevent the accumulation of rain in the smoke box [0 and to reduce down drafts in the chimney, there is provided a battle 3| extending across the bottom of the throat 9 where it opens into the smoke box. This baflle is disposed at an inclination to the vertical so as to turn back upon itself any down-current of air within the chimney and thus dissipate its effect, the fiat bottom of the smoke box also contributing to this result. The bafile additionally serves to dam the water collecting within the bottom of the smoke box, such as may occur in the case of heavy or protracted downpours, and the accumulated water is drained off through a bleed pipe 32 extending from the bottom of the smoke box to outside the enclosure.

The operation of the dual heating system described above is as follows: With the primary heater A in operation, the baii'le plate 5 will cause the hot gases of combustion to sweep the enclosing walls of the casing I giving up a large part of its heat thereto and insuring an efiicient transfer of heat throukh these walls to the air moving through the heat chest. These combustion gases will then pass off through the metal flue pipe l, heating the air contained within the surrounding riser E.

With the deflector plates 23 in lowered position, the air delivered by the blower [9 into the heat chest through the open bottom 22 of the housing will be deflected away from the end walls of the fireplace shell 8 and into contact with the walls of the casing l enclosing the oil burner, thus preventing the shell from robbing the return air of a substantial portion of its residual heat.

The circulation air after leaving the heat chest enters the riser E where any loss of heat as a result of absorption through the walls of the chimney is replenished by heat transferred thereto through the metal flue pipe I. Thus, the circulation air is maintained at a high temperature until it leaves the riser through the distributing duct F. The heated air is discharged into the enclosure through the register 30 to heat the enclosure. As the circulation air loses its heat, it sinks towards the floor level and is returned via the grilles 20 and return-air pipes G to the air chamber D where it repeats its heating cycle.

When the auxiliary heater B alone is in service,

or when both the primary and auxiliary heaters A and B are operating in conjunction, the handle 21a on the cross-rod 21 is turned so that the damper 26 is opened and the deflector plates 23 are raised, allowing the gases of combustion to pass out of the fireplace into the chimney I! through the throat 9 and at the same time permitting the air passing up into the heat chest C through the opening 22 to flow against the hot surfaces of the end walls of the fireplace shell and recuperate a substantial amount of heat therefrom. The circulation air heated by the burner casing, the fireplace shell, or by both, then enters the riser E and travels the same circuit as previously described, returning to the air chamber D via the return-air pipes G.

It will be apparent from the foregoing description that the auxiliary heater B may be used by itself to take the chill on of the air within the home or it may be used contemporaneously with the primary heater A without interfering with the operation of the latter. By virtue of the coordinated operation of the damper 26 and the deflector plates 23, the dual heating unit is adapted to provide the most ef ficient heatin of the home by preventing inflow of cold outdoor air by way of the throat 9 and by deflecting the circulation air, which retains a portion of its heat after travel through the enclosure, out of contact with the cold metal plates at opposite ends of the fireplace shell.

The dual heating system described above is especially suitable for homes located in climates subject to sudden changes in temperature when the use of a fireplace alone is suflicient to take the chill off of the home but Where it is impracticable to keep the fireplace going throughout a lengthy cold spell. During such latter interval, the oil or gas burner will be switched into service to heat the home, either independently of or in conjunction with the fireplace.

Ordinarily the air leaving the heat chest would start losing heat and undergo an appreciable lowering of temperature by the time it is discharged through the registers 38 into the enclosure. However, by virtue of my construction in which the flue 1 of the primary heater is led upwardly through the riser E, the heat in the circulation air is conserved, thus increasing the efiiciency of the system by reducing heat losses between the heat chest and the points of discharge of the air into the enclosure.

While I have described the auxiliary heater as a coal-burning or wood-burning fireplace, manifestly other types of fuel may be employed, or the fireplace may be electrically heated.

It will usually be found desirable to provide a thermostat within the enclosure for automatically controlling the operation of the primary heater A, but since such temperature control means are well known in the heating art it is not necessary to describe such means.

The heating system just described will be found particularly advantageous for installation in homes situated in localities where it is impracticable to construct basements because of the likelihood of flooding during rainy seasons. Because the air chamber may be located in the space between the ground level and the first floor of the house, virtually no excavation is necessary. When a forced circulation system is not desired, the blower l9 may be omitted and a straight convection system for the circulation of the air within the enclosure may be employed, the cold air returning to the heat chest through grilles suitably provided in or adjacent the floor level and feedin into the air chamber. In such cases, however, it will usually be found more satisfactory to mount a fan in the attic or elsewhere at some convenient place in the home for aiding the movement of air.

While a preferred specific embodiment of the invention has been set forth, it is to be understood that the invention is not limited to the exact constructions illustrated and described, but modifications of these details may be made within the purview of the appended claims.

I claim:

1. A dual heater unit adapted to be installed within the fireplace area of a home, said unit comprising an open-front fireplace shell having end walls and a back wall, a casing located rearwardly of the back wall of the shell and containing a burner, and a housing enclosing said casing and the end and back walls of the shell in spaced relation thereto, a conduit leading from adjacent the top of the shell to the exterior of the housing for the removal of combustion products from the shell, a flue extending outwardly from the casing through the housing for the removal of combustion products from the casing, said housing being open at its bottom to provide openings for the admission of air through the space between the corresponding end walls of the shell and housing, a warm air outlet in the housing adjacent its upper end, deflectors ad justably mounted between the said end walls adjacent the air-admission openings for directing the air into and out of heat-exchange relation with the end walls of the shell, and control means for adjusting said deflectors.

2. A dual heater unit as set forth in claim 1 including an air chamber located below the housing and communicating with the housing through the air-admission openings.

3. A dual heater unit as set forth in claim 1 including an air chamber located below the housing and communicating with the housing through the air-admission openings and a blower located in said air chamber for producing forced circulation through said air chamber and hous ing.

4. A dual heater unit as set forth in claim 1 in which the flue extends through the warmair outlet vent in the housing.

5. A dual heater unit adapted to be installed within the fireplace area of a. home, said unit comprising an open-front fireplace shell having end Walls and a back wall, a casing located rearwardl of the back wall of the shell and containing a burner, and a housing enclosing said casing and the end and back walls of the shell in spaced relation thereto, a conduit leading rearwardly from the top of the shell to the exterior of the housing for the removal of combustion products from the shell, a damper pivotally mounted for opening and closing said conduit, and a flue extending from the casing through the housing for the removal of combustion prod ucts from the casing, said housing being open at its bottom to provide openings for the admission of air through the space between the correpsonding end walls of the shell and the housing, a warm-air outlet in the wall of the housing adjacent its upper end, deflectors pivotally mounted between said end walls adjacent the air-admission openings for directing the air into and out of heat-exchange relation with the end walls of the shell, and common control means for simultaneously adjusting the positions of the Number damper and the deflectors. 1,984,933 ROBERT D. RUSSELL. 2,102,727 2,227,086 REFERENCES CITED 5 2 243 75 The following references are of record in the 2,355,495 file of this patent: 2,402,907

UNITED STATES PATENTS Number Name Date 10 Number 1,857,480 Schonberger May 10, 1932 5,561 1,877,421 Munkel Sept. 13, 1932 Name Date Kuenhold Dec. 18, 1934 Maher Dec. 21, 1937 Hayter et a1. Dec. 31, 1940 Donley May 27, 1941 Zier Aug. 8, 1944 Mueller 1- June 25, 1946 FOREIGN PATENTS Country Date Great Britain 1895 

